Sahih al-Bukhari 3251
صحيح البخاري#3251SahihNarrated Anas bin Malik:The Prophet (ﷺ) said, "There is a tree in Paradise (which is so big and huge that) if a rider travels in its shade for one hundred years, he would not be able to cross it
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Every narration in Sahih al-Bukhari is accepted as Sahih (authentic) by the established status of the book.
In-book reference: 59:62